Sane SvStream* fake pointer values for 64-bit platforms
Sane SvStream* fake pointer values for 64-bit platforms

cf. <https://gerrit.libreoffice.org/#/c/13659/3> "Signed/Unsigned mismatch on
x86_64 platform on windows"

Change-Id: Ie526ee431f59be374d61fe8c38bdf2a579a7234b

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core